It is desirable to provide compositions which have beneficial effects on wet and dry hair, for example which improve handle, softness, silkiness, and ease of combing the hair. Such beneficial effects may be obtained by incorporating certain types of silicones into hair care compositions. The preferred silicones include alkyl- or aryl-functional polydiorganosiloxanes. However, such compounds are not easily incorporated and result in opaque or at best translucent hair care products. It is aesthetically desirable to provide optically clear hair care compositions.
Silicones in hair care compositions have been disclosed in a number of different publications. For example, in U.S. Pat. No. 4,788,006 is disclosed shampoo compositions which comprise a synthetic, anionic surfactant, a dispersed, insoluble, non-volatile silicone, a xanthan gum suspending agent and water.
Hair treating compositions containing aminofunctional polysiloxanes have also been described. For example, in U.S. Pat. No. 4,563,347 it is disclosed that an aqueous emulsion of aminoalkyl substituted polydimethylsiloxane is useful to condition hair because it facilitates combing and imparts a smooth feel to hair. The aminoalkyl substituents are credited with providing the copolymers with cationic sites that make the polymer more substantive to hair than nonsubstituted polydimethylsiloxane. The '347 patent further teaches the use of aminofunctional polydiorganosiloxane solutions and emulsions as conditioners. Other hair treating compositions containing amino functional polysiloxanes are described in U.S. Pat. Nos. 4,586,518, 4,601,902, and 4,618,689, however these references do not describe the use of microemulsions in these compositions.
Aminofunctional microemulsions have also been described in the art. For example, in U.S. Pat. No. 4,749,732 is disclosed the use polydiorganosiloxanes containing aminoalkyl groups modified by alkoxycarbonylalkyl substituents in hair care compositions. The '732 patent also teaches that the modified aminoalkyl silicones exhibit improved deposition on hair and can be formulated into shampoos or conditioners. The '732 patent states that microemulsions of modified aminoalkyl substituted polydiorganosiloxane can be prepared by the method described in U.S. Pat. No. 4,620,878 which describes generally the preparation of emulsions of silicones containing polar substituents. The '732 patent does not disclose how to prepare these modified aminoalkyl substituted polydiorganosiloxane microemulsions. Further the '732 patent does not disclose an unmodified or unsubstituted amino functional microemulsion as an ingredient in an optically clear silicone formulation. In addition, these modified amino substituted microemulsions utilize acrylic monomers which give rise to serious odor problems making the materials unsuitable for cosmetic use.
The '878 patent teaches a method of preparing clear microemulsions of aminofunctional polyorganosiloxanes. It is further disclosed in Example 24 of the '878 patent that transparent microemulsions of aminofunctional siloxanes can be mixed with a shampoo base of sodium laurel ether sulfate and water to produce a stable, clear composition. However, the '878 patent does not teach an aminofunctional microemulsion as an ingredient present in an optically clear shampoo composition. Example II and Comparative Example I of this specification clearly illustrate the unexpected advantages of this invention over the composition described in Example 24 of the '878 patent.
In U.S. Pat. No. 4,559,227 a conditioning shampoo composition is taught containing a nonionic surfactant of the alkanolamide or amine oxide type, an aminofunctional polydiorganosiloxane as a hair conditioning component, a detersive surfactant of the anionic or amphoteric type, and water, the shampoo composition being in the form of an aqueous solution. The '227 patent further discloses a method of preparing the shampoo composition as a stable solution. This is in contrast to this invention which employs pre-made microemulsions as opposed to solutions as components to provide optically clear silicone compositions. The use of the premade microemulsion allows an easier to use shampoo to be formed without a complex premixing of the composition.
Polydiorganosiloxane microemulsions have also been described in the hair care art. For example, European Patent Publication No. 268,982 discloses cosmetic compositions containing microemulsions of dimethylpolysiloxanes produced by emulsion polymerization which provide long term storage stability. However, the formulations of the '982 application do not disclose a aminofunctional silicone microemulsion as an ingredient in an optically clear silicone composition that provides substantive conditioning.
In U.S. Pat. No. 5,063,044 is disclosed a hair conditioning composition being a mixture including water, a thickener, and an organosilicon compound. The organosilicone compound can take the form of a microemulsion and is selected from the group consisting of carboxy glycol ether and carboxy-glycol ester functional polysiloxanes, which are appreciably polar and soluble molecules. In contrast, this invention utilizes a non-polar insoluble aminofunctional polydiorganosiloxane microemulsion in combination with certain materials to unexpectedly provide true optical clarity to the silicone compositions of this invention along with robust, substantive conditioning when applied to hair.
This invention can therefore be distinguished from the references enumerated above in that this invention contains an aminofunctional silicone microemulsion in combination with certain materials to provide truly optically clear shampoo compositions that have beneficial effects greater than the hair care formulations known in the art, and in view of the fact that the cationic compounds of the prior art do not generally deposit well from shampoo compositions containing anionic detersive surfactants, it is surprising that the aminofunctional microemulsion is so effectively deposited from the shampoo compositions of this invention which can contain anionic detersive surfactants and at the same time retain clarity and stability. Therefore, since the shampoo compositions of this invention provide a unique and advantageous combination of superior foaming, and provide a clear and easy to use product with increased substantive conditioning properties, they are advantageous over the formulations of the art.